This invention relates to an ignition system for a fluidized stream of finely-divided coal particles in a pressurized gasifier housing wherein a pipe extending into the gasifier housing is employed for an overflow slag discharge.
In the process of high pressure gasification, fuel in the form of fine particles or dust is fed together with gasifying agents as a fluidized stream toward the bottom of a reaction chamber for gasification at temperatures of up to 2200.degree. C. according to known gasifier constructions. Fluidized streams are formed by a plurality of main burners extending preferably tangentially and obliquely downwards toward the bottom of the reaction chamber. The gases produced are withdrawn from the top of the gasifier. Liquid slag in the bottom of the gasifier drips into a water bath where the slag granulates and undergoes discharge by way of lock systems.
To obtain the optimum operating temperatures in the gasification chamber, it is initially heated with gas. The main burners can be used for the gas supply in this case. It is known prior art to include the provision of ignition systems on the main burners to insure reliable ignition of relatively large amounts of gas.
Conventional ignition systems of this type do not withstand conditions within the environment of the gasification chamber and a specific ignition burner intended, for example, for the ignition of gas cannot be changed for the ignition of a jet stream of coal/oxygen.
Upon ignition and start-up of such pressurized gasifiers, a number of different operational states are passed through in a continuous manner before a steady-state operation is attained. It is desirable to heat up the reaction chamber while in an unpressurized state by means of one fuel, e.g., gas or oil, and then change over to the use of a fluidized stream of coal feedstock without the necessity for outside operations to effect the changeover operation. For example, the changeover operation should be carried out without the removal and fitting of parts in the reaction chamber of the gasifier.